Light screen



E. E. RICHARDSON April 23, 1929.

LIGHT SCREEN Filed Nov. 19, 1927 311 vewtoz atto: um;

Patented Api. a3,- 1929.

l UNITED STATESl PATENT ,o1-*Fica EDWARDv E. RICHARDSON, or-munan, omo.

menu: scam.

Application mea November 19, 19427. serial no. 234,431.

My invention has for its object to provide a means for preventing lightfrom an\e xternal Source producing colored signal lights in connectionwith an form of a light indicator to enable correct mte'rpretation ofthe signals and prevent confusion or uncertainty as to the signalintended to be given. The invention particularly has for its object toprovide a means for preventin the characteristic lighting of signallinevices by the reflected sunlight, particu arly when'the sun is locatedata low angle, which ordinarily produces confusion as to the indicationintended by the operation of the signalling device.

The invention may be contained in signalling devices of different formsthat are dependent upon the transmission of light through translucentmaterial, or a material or materials of distinctive color or colors,and, to illustrate a practical application of my invention I haveselected a structure containing the lnvention as a'n example of suchstructures and shall describe it hereinafter. The structure selected isshown in the accompanying drawings. i

Fig. 1 is a perspective view of the particular example selected forpurposes of illustrationto show a light screen embodying my invention.Fig. 2 illustrates a. signalling device of the type commonly used inconnection with tralic signals, it being provided with a plurality ofindicating elements to direct the traiic and to which my invention isshown applied.` Fig. 3 is an enlarged view of one side portion vof thelight screen, and illustrates thel manner in which the device may besecured in position. Fig. 4 is a side View of a part of the device andillustrates the displaced relation of the device with respect to a lensof the signalling device. The device embodying my invention comprises atranslucent means which is preferably so formed as to cause a diffusionof a large part of the light that passes through the device. Thus thedevice provides a means for causing diifusion of the rays of light thatmay be directed into the lamp of the signalling device from a sourceexterior to the lamp which revents the uniform reflection of the raysof) light by the reflector of the device that ordinarily would producesubstantially the same effect that is produced by the lighting of thebulb of the signalling device. Where the sun shines directl into adevice, as where the sun is near the p ane of the horizon, thereflcctionof the raysof light of the sun from the reflector of the lampproducessubstantially the same signal as would be produced by thelighting of the bulb 'of the lamp and, by breaklng up or reducing theintensity vof the sunlight, the effect is so diminished that the lihting of the bulb will produce the desire variation in intensity of thecharacteristiclight that the signal will be transmitted or there will besuch a marked change in the intensity of the characteristically coloredlight that thefsignal will be received and may be responded to by thoseobserving the signal. Thus, by my invention I have provided a means forreducing the intensity of the rays of the sunlight to enable the lightof the signalling element to produce the desired indications.

In the particular form vof. construction shown in the drawings, thetranslucent material or the substantially translucent member is made inthe form ,of a wire screen that may be located in front of the lens ofthe signalling device. The wire screen 1 ma be provided with a suitablereinforcing r1m 2 that ma 1 be mounted in front of a lens 3. Where t1ere are a pluralit of signalling devices having a plurality o lenses, ascreen is located preferably in front of each of the lenses. In theforni of construction shown, vthe signalling devices are each providedwith a visor, such as the visor 4 and suitable engaging members 5 areconnected to each side of the rim 2 and in position to engage the sidesof the visor 4. The engaging member may consist of a. spring bar 6,which is secured to the rim 2, and a cross bar 7, that may also beformed of elastic material, is connected to the end of the bar 6. At theends vof the bar 7 are located a pair of engaging members, such asfrictionally engaging compressible members, such as rubber blocks 8,which will frictionally engage the edge of the visor 4 and hold the'screen 1 in position.

The screen 1 is preferably located in slightly spaced relation withrespect to the front of the lens 3 in order to prevent the lightrelected from the front of the lens from passing out through thel sameopenings in the screen to the eye of the individual who may able to varythe quantity of light that may be permitted to enter the signallingdevice from an external source, such as from the sun, 1n order that themaximum amount of characteristically colored light may be produced whenthe bulb of the signalling device is lighted. Thus, I have found that,Where an amber lens is used, a large portion of the rays of light fromthe external source should be cut off owing to the fact that the amberglass transmits practically all of the llght from the bulb and alsotransmits the larger portion of the light from the sun. In theconstruction embodying my invention, where an amber colored glass isused in the open and subject to the sunlight when the sun is at a lowangle, the entire lens is preferably covered by the light screen 10 toeliminate a large portion of the reflected light from the sun that maystrike the reflector of the signalling device, the amber colored glassoperating to transmit substantially all of the light of the light bulb,will produce a sufiicient distinctive signal to be observed.

lVhere the lens is formed of red glass, there is a lesser transmissionof the suns rays to the reflector of the signalling device and also alesser transmission of the rays from the bulb, and, consequently, it ispreferable to provide for an increase of the rays of light from thebulb. Thus, the area of the lens covered by the screen may be decreased,to provide for this variation of the proportionate amount of the lightthat is transmitted from the two sources. Also it has been observedthatthe bulb, which is invariably located at the center of the reflector,causes the sunlight to be reflected from the surface of the glass of thebulb to the peripheral portions of the reflector and does not reflectdirectly back to the center of the lens. On the other hand, the lightfrom the bulb will be transmitted through the top of the bulb andthrough the center of the lens, which will produce a marked change inthe light at the center of the lens when the bulb is lighted. Hence, Ifind it preferable to form the opening 11 in the center of the screen.

Where the signalling device is provided with a green lens, a stilllesser quantity ofv light is transmitted through the lens either modestfrom the sun or from the bulb and, consel vided with a central opening12 that is larger `than the one that is used Where the lens is red.

Thus, by my invention, the translucency and the characteristic qualityof the construction embodying my invention may be varied to produce themost efficient results according to the translucency o-r color of thetransparent element that is used to cover the bulb and reflector of thevsignalling device. My invention thus provides a means for obviating theconfused condition created by the reflection of a light from a sourceexternal to the signalling device.

I claim l. In a light screen for signaling devices having a light bulb,a reflector and a colored lens, a rcticulated screen coveringsubstantially that portion of the lens other than that opposite to thelight bulb to permit direct light to pass from the light bulb throughthe portion of the lens not covered by the screen, the light from asource outside of the signaling device being deflected by the light bulband by thescreen the relation between the light transmitting propertiesof the lens and l the sizeof the central opening in the screen beingsuch as to prevent a. phantom indication.

2. In a liUht screen for associated signaling devices eac i having alight bulb, a reflector, and a colored lens, a reticulated screencovering substantially that portion of each lens other than thatopposite to the light bulb for diffusing the rays of light from a sourceexternal to the signaling device to permit direct light to pass from thelight bulbs through the portions of the lenses not covered by thescreens, the light from an external source passing into the casingthrough the portion of the lenses not covered by the screens beingdeflected by the light bulbs, the areas of the portions of the lensesnot covered by the screens varying inversely in area according to thelight transmitting properties of the lenses.

In Witness whereof I have hereunto signed my name to this specification.

EDWARD E. RICHARDSON.

